It'll start getting up there in late May and June... you should be about ready to leave by July.
Just dress comfortably when you're outdoors and you'll be okay... hopefully you won't see any 100+ degree days... most of those are over into late July and August... sometimes even September.
Hey, it can't be too bad... people do still live here year round.
If you like minor league baseball, check into the Charleston Riverdogs... beautiful ballpark down by the Ashley River.
http://www.riverdogs.com/